Health & Pregnancy

Pregnancy Essentials

Topic Overview

This topic is for women who
are pregnant with more than one baby. It focuses on the questions that are
specific to multiple pregnancies. For information on what to expect during
pregnancy, labor, and childbirth, see the topic
Pregnancy.

A multiple
pregnancy means that a woman has two or more babies in her
uterus. These babies can come from the same egg or
from different eggs.

Babies that come from the same egg are called
identical. This happens when one egg is fertilized by
one sperm. The fertilized egg then splits into two or more
embryos. Experts think that this happens by chance. It
isn't related to your age, race, or family history.

If the babies
you're carrying are identical, they:

Are either all boys or all
girls.

All have the same blood type.

Probably will
have the same body type and the same color skin, hair, and eyes. But they won't
always look exactly the same. They also won't have the same
fingerprints.

Babies that come from different eggs are called
fraternal. This happens when two or more eggs are
fertilized by different sperm. Fraternal twins tend to run in families. This
means that if anyone in your family has had fraternal twins, you're more
likely to have them too.

If the babies you're carrying are
fraternal, they:

Can be both boys and girls.

Can
have different blood types.

May look different from each other or
may look the same, as some brothers and sisters do.

Fertility drugs
help your body make several eggs at a time. This increases the chance that more
than one of your eggs will be fertilized. When in vitro fertilization is used to help a woman get pregnant, the doctor may put several fertilized eggs in the uterus to increase the chances of having at least one baby. But this also makes
a multiple pregnancy more likely.